"Psychological development "is a matter or self
understanding, self acceptance, and personal integration. The former
(mystical path) involves itself with self-forgetting, the disappearance of
the self into mysterious union with God, Absolute, the Transcendent aspect
of reality, the Tao. Thus the term self-transcendent (with emphasis on the
small "s" self in the self, as opposed to the Self, higher aspect
of the personality) means letting go of egoistic interests and practical,
worldly matters."

Sinetar - Ordinary People as Monks and Mystics.

"Mystical science is for those who can obtain
satisfaction of their worldly need from appropriate sources and do not seek
them, in disguise, in the spiritual domain. Worldly need must be satisfied
elsewhere so that their pursuit does not interfere with there learning
process. Similarly, psychopathology must be dealt with first. Consequently
there is no way for mysticism to substitute for psychotherapy, or visa
versa."

Deikman - The Observing Self

But you have to be somebody before you can be nobody. The
issue in personal development as I have come to understand it is not self or
no-self, but self and no-self. Both a sense of self and insight into the
ultimate illusoriness of its apparent continuity and substantiality are
necessary achievements. Sanity and complete psychological well-being include
both, but in a phase-appropriate developmental sequence at different stages
of object relations development. The attempt to bypass the developmental
tasks of identity formation and object constancy through a misguided
spiritual attempt to "annihilate the ego" has fateful and
pathological consequences. This is what many students who are drawn to
meditation practice and even some teachers seem to be attempting to do.

Jack Engler - Transformations of Consciousness

What Buddhist psychology and practice appear to do
instead is presuppose a more or less normal course of development and an
intact or "normal" ego.